Conveyor



United States Patent Inventor .lohn Louis Rudlafl' [56] References Cited Plymouth, Michigan UNITED STATES PATENTS pp 794,851 3,322,259 5/1967 Milazzo 198/219 Filed Jan. 29, 1969 Continuation-impart of application Ser. No. Pmnary "P Aegener 730,758 May 21 1968, now abandoned AttorneyCurtis, Morris and Safford Patented Dec. 8, 1970 Ass'gnee Adel Laboratmes ABSTRACT: An accumulating conveyor is disclosed having a Livonia Michigan plurality of stations, a reciprocating mechanism for advancing parts and a mechanically operated control for advancing parts rearwardly of an empty station and preventing the advancement of parts forwardly of the empty station comprising, a link-bar at each station cooperating with the reciprocating mechanism to cause it to engage and advance a part when the link-bar is in one position and disengage and move relative to CONVEYOR a part when the link-bar is in another position, and a mechani- 30 Claims 17 Drawing Figs cally operated sensing element at each station actuated by the US. Cl. 198/221, weight of a part to move a cooperating link-bar into alinement 198/219 with the next adjacent link-bar to transmit motion through Int. Cl. B653 15/00 successive stations to an empty station and interrupt the trans- Fleld of Search 198/218, mission of motion to the next adjacent link-bar at any empty 219, 221, ]9 station to control the position of the link-bar at each station.

1 p O I I94 5 P 7 I X a I I I t I 1 v i i. 1.. 'i .4 38

'2 a. \1 4 a A t i PATENTED DEC 8 I970 SHEET 1 BF 9 QMWQWA Q INVENTOR. JOHN L. RUDLAFF haw ATTORNEYS STATION 5 STATION 6 '59\ 47 in. 60 INVENTOR. :44 43 44 43 JOHN L.RUDLAFF ATTORNEYS PATENTEDBEC 819m 3.645.600

' SHEET 3 0F 9 INVENTOR. JOHN L. RUDLAFF ATTORNEYS PATENTED'DEB 8 I970 SHEET [1F 9 INVENTOR. JOHN L. RUDLAFF QAZZ ATTORNEYS PATE NTEB um 8 mm sum 7 or 9 INVENTOR JOHN L RUDLAFF m ZOE/2m ATTORNEY PATENTEU DEC 8 I970 SHEET 8 BF 9 NVENTOR JOHN L. RUDLAFF ATTORNE I CONVEYOR The present invention relates to conveyors and more particularly to accumulating conveyors which which operate automatically to maintain a supply of parts as they are needed. This application is a continuation-in-part of my prior application Ser. No. 730,758 filed In May 21,1968 now abandoned, and entitled Cone Conveyor, and relates back to my prior application for all common subject matter.

Modern manufacturing techniques require the feeding of parts to an assembly line by automated equipment to eliminate the cost of handling and avoid delays. Thus, conveyors have been used for this purpose which are-controlled pneumatically, hydraulically and electrically. Such conveyors are designed to continually advance parts to any station without feeding any part forwardly of the empty station and have been quite successful in reducing the down time on assembly lines. Also the accumulating conveyors insure a proper handling of the parts which reduces the possibility of damage of parts to a minimum.

However, the pneumatic, hydraulic and electrical controls have sensing elements such as valves and switches which are subject to failure. As a result a continual search has been in progress to find a commercially practical accumulator transfer mechanism that is positively operated mechanically to further reduce the possibility of failure of the sensing element of the control.

One of the objects of the present invention is to provide an improved mechanically operated accumulating conveyor for maintaining a supply of readily available parts as they are needed.

Another object is to provide an improved mechanically actuated conveyor in which the weight of a part mechanically controls the transmission of a motion which is used to prevent the advance of parts at all stations forwardly of an empty station and interrupt the transmission of the motion to all stations rearwardly of the empty station to cause parts to be advanced.

Another object is to provide a mechanical control for an accumulating conveyor which is of a relatively simple and compact construction, economical to manufacture and one which is reliable in operation. These and other objects will become more apparent from the following description and drawings in which like reference characters denote like parts throughout the several views. It is to be expressly understood, however, that the drawingsare for the purpose of illustration only and are not a measure of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings:

FIG. 1 is a side elevational view of an accumulating conveyor incorporating novel v features of the present invention and showing a part at all of the stations except one;

FIG. 2 is an end view of the accumulating conveyor illus trated in FIG. I and showing the relationship of the reciprocating mechanism for advancing parts and control mechanism for setting the position of the part engaging dogs;

F IG. 3 is an enlarged side elevational view of two stations of the conveyor illustrated in FIG. 1 and h showing the cams for actuating the part engaging dogs to a disengaging position at an empty station and releasing the dogs to a part engaging position at the station rearwardly of said empty station;

FIG. 4 is a view similar to FIG. 3 showing the relationship of the parts after a forward stroke of the reciprocating mechanism;

FIG. 5 is a side elevational view of an accumulating conveyor of modified construction to lift and carry parts and having a vertically moving perch at each station which is operated by the weight of a pr part to control the transfer of parts in accordance with the present invention;

FIG. 6 is an enlarged side elevational view of the motion transmitting link-bars for controlling the position of the perches;

FIG. 7 is a plan view of the conveyor stations illustrated in FIG. 6;

FIG FIG. 8 is an end view of the upper portion of the accumulating conveyor illustrated in FIG. 6- and showing the shoulder on a link-bar actuated to a position to lock a perch in its upper position;

FIG. 9 is a side elevational view of a shuttle type accumulating conveyor of a still further modified construction having the control link-bars mounted on the shuttle and a rockable sensing bar mounted on the frame and operated by the weight of a part for directly actuating its corresponding link-bar;

FIG. 10 is a plan view of the accumulating conveyor illustrated in FIG. 9;

FIG. 1 1 is a transverse sectional view taken on line 11-11 of FIG. 9 to show the mounting of the link bars directly on the shuttle;

FIG. 12 is a sectional view taken on line 12-12 of FIG. 9 to show the dogs on the transfer bar for advancing parts;

FIG. 13 is a plan view of a section of an accumulating conveyor showing the present invention applied to a walking beam type of conveyors;

FIG. 14 is a side elevational view of a construction illustrated in FIG. 13 and showing a modified sensing control arrangement including blocks between adjacent link-bars with each block having a cam for raising and lowering the perches;

FIG. 15 is an end elevational view of the modified arrangement illustrated in FIGS. 13 and 14;

FIG. 16 is a side elevational view ofa further modified construction for controlling the advance of parts at the last two stations adjacent the exit end of the conveyor to adapt the end of the conveyor for cooperation with other equipment adjacent its end; and

FIG. 17 illustrates a still further modified construction at the endmost station for delivering parts to a loader for auxiliary equipment.

The invention relates to accumulating conveyors having a reciprocating mechanism with a part-advancing means thereon at each of a plurality of stations and controlled to advance parts at the rear of any empty station without advancing parts forwardly of the empty station to maintain the conveyor completely filled with parts at all times. The control comprises a link-bar at each station which may be mounted for pivotal movement into alignment with the other links or connected through intermediate links to the link-bar at the next adjacent station. When the link-bars or link-bars with cone connecting links at the adjacent stations are positioned in line they will transmit motion, but when one of the link-bars or connecting links is moved out of line with its adjacent link-bar at any station the transmission of motion to the next adjacent link-bar will be interrupted. The endmost link of the series is reciprocated, first in one direction and then in the opposite direction, at some time prior to the forward stroke of the partadvancing mechanism. The position of the link-bar or connecting link at each station, either in-line or out-of-line with the adjacent link-bars, controls the movement of all link-bars forwardly and rearwardly of the empty station during a reciprocation of the endmost link. Each link-bar or connecting link, in turn, is maintained in line or actuated to an out-ofline position by a mechanically operated sensing bar at each station which is responsive to the weight of a part. Also, the position of the link-bar at each station controls the operation of the part-advancing means at its station. Thus, after reciprocation of the endmost link, the part-advancing means at each station is set by the position of the next adjacent link-bar to either engage or not engage a part at said station, and when the transfer bar or carriage is reciprocated through a forward stroke all parts rearwardly of an empty station will be advanced and all parts forwardly of the empty station will not be advanced.

The link bars and interconnecting links of the present invention may be reciprocated first forwardly and then rearwardly, or first rearwardly and then pushed forwardly to set the partadvancing means at each station. Also, the link-bars and connecting links of the present invention are adapted to controi the position of the pivoted go dogs of a shuttle type conveyor, the moving perches of a lift-and-carry type conveyor, or the part-engaging elements of a walking beam type conveyor.

When the link-bars and connecting links of the present invention are applied to a shuttle type conveyor the part-engaging dogs may be operated by gravity to either a part-engaging or a part-disengaging position and actuated to the opposite position by the movement of its corresponding link-bar. When the invention is applied to a lift-and-carry type conveyor the movable link-bars may operate to raise the perch or hold it in its lower position. When the invention is applied to a walking beam type conveyor. the link-bars may position the part-supporting elements to engage a part or not engage a part, dependent upon whether or not a part is present at a forward station.

Referring now to the drawings, FIGS. 1 and 2 illustrate an accumulating conveyor having a frame 1 supported by spaced legs 2 at opposite sides. The frame comprises side plates 3 and 4, see FIG. 2, of build up sections and forming spaced rails at their upper edges on which parts can slide and which have spaced notches providing spaced stationary seats 5 and 6 at each of the stations 1 to 10, see FIG. 1. Projecting inwardly from the side plates 3 and 4 adjacent their lower edges are opposed sets of rollers 7 and 8, see FIG. 2, for mounting a carriage 10 constituting a reciprocating mechanism. The carriage 10, in turn, has side plates 11 and 12 of built up sections connected by cross-struts 13. The lower edges of the side plates 11 and 12 of carriage 10 provide rails for rolling engagement with the rollers 7 and 8 to mount the carriage for reciprocating movement. The carriage 10 is shown in its rearward position in FIG. 1 and is operated through a forward stroke by a hydraulic motor 14 as controlled by a valve 15 which, for purposes of simplicity of illustration, is shown electrically controlled.

The parts P to be accumulated and advanced are illustrated as crank shafts having their end bearings cradled in the V- shaped notched seats 5 and 6 at each station in the stationary side plates 3 and 4 of the frame. It will be understood, however, that the parts may have other shapes. The parts P are advanced by a pair of part-engaging dogs 19 and 20 at each station which are connected by a crossbar 23. The dogs 19 and 20 are pivotally mounted on pins 21 and 22 projecting inwardly from the side plates 11 and 12 of the carriage 10, see FIG. 2, for rocking movement by gravity to an operative partengaging position as illustrated at stations 1 to 6 in FIG. 1.

Dogs 19 and 20 have forwardly projecting fingers 19a and 20a for engaging intermediate bearing portions of the crank shaft and counterweights 19a and 201912 and 20b at the opposite sides of the pivot pins 21 and 22 from the part-engaging fingers. The dogs 19 and 20 are adapted to be rocked by the counterweights 19b and 20b to a part-engaging position to engage and push a part P forwardly along the side plates 2 3 and 4 of the frame 1 during a forward stroke of the reciprocating carriage 10, and to be rocked to a part-disengaging position, see FIG. 3, against the gravity of the counterweights 19b and 20b to a part-disengaging position during the forward stroke of the carriage. The depending counterweight 19b of the dog 19 is provided with a shoulder 190 for engagement with stop pins 24 on the side plate 11 of carriage 10 to limit the rocking movement of the dogs by gravity to a part-engaging position. Dog 19 also has an inwardly projecting follower tab 25 for engagement by a cam 26, later to be described, for rocking the dogs 19 and 20 clockwise against the action of gravity to its inoperative part-disengaging position illustrated at the station 5 in FIG. 4. In this inoperative position of the dogs 19 and 20, the part-engaging fingers 19a and 20a are located below the bearing portions of the crank shaft so that they will pass under the crank shaft P during a forward stroke of the reciprocating carriage 10.

In accordance with the present invention a novel construction and arrangement of the reciprocating carriage 10 of the of elements is provided for setting the dogs 19 and 20 at each station 1 to 10 to a part-engaging or part-disengaging position prior to the forward advance stroke of the reciprocating carriage 10. Furthermore, the arrangement is such that a motion is applied to a control mechanism at one end of the conveyor which is transmitted through all stations forwardly of any empty station to set the dogs to an inoperative position and set all of the dogs rearwardly of the empty station to a part-engaging position.

The control mechanism for setting the dogs comprises a reciprocating link-bar 28, sometimes referred to as a read-out bar, at each station which, when aligned with corresponding link-bars at other stations, form a continuous bar from one end of the conveyor to the other. However, when a link-bar 28 at any particular station is moved out of alignment with the other link-bars it will interrupt the motion transmitted from one end of the conveyor at one side of the out-of-line link-bar to prevent motion to the link-bars at the other side of said linkbar. For this reason the link-bar 28 may be considered as a read-out bar to control the operation of the dogs 19 and 20.

As illustrated in FIG. 3, each link-bar 28 is pivoted at one end on a pin 29 having its ends projecting into blocks 30 and 31 slidable in slotted guideways 32a and 33a in spaced guide tracks 32 and 33, in turn, are supported by beams 34 extending between opposed pairs of legs 2 spaced longitudinally of the frame. Thus, the link-bar 28 at each station is free to rock downwardly to the position illustrated in FIG. 3, and out of line with a corresponding link-bar at the next adjacent station or into alignment with the other link-bars to form a continuous bar as shown in FIG. 4. Link-bar 28 underlying the station 5 rearwardly of empty station 6 is shown in FIG. 3 as rocked downwardly about pivot pin 29 to an out-of-line relation to the link-bar at next adjacent forward station 6 to interrupt the transmission of any motion rearwardly of station 6. However, when the link-bar 28 at station 5 is rocked into alignment with the other link-bars at successive stations as shown in FIG. 4, it will transmit the motion from the link-bar at station 6 to the link-bar at station 4. Each link-bar 28 may constitute a single element, but in the illustrated embodiment it is shown as comprising two link-bars 28 and 28a 1280 as illustrated in FIG. 2. Both of the link bars 28 and'28a are mounted on the pivot pin 29 at oppositesides of the cam 26.

Underlying the cam 26 is a roller 35 rotatable on a pin extending between the guide tracks 32 and 33 which engages a cam surface 36 on the underside of the cam for rocking it upwardly from the position shown at station 5 in FIG. 3 to the position shown at the same station in FIG. 4. Cam 26 also has an upper edge surface 37 which rides under the follower tap tab 25 on the dog 19 to rock both dogs 19 and 20 to their in- Operative position.

The link-bar 28 at each station is actuated to an in-line or out-of-line relation by a mechanical linkage including a sensing element 38 at the next adjacent forward station. While the sensing element 38 at each station may take other forms, in the illustrated embodiment is it is shown as a bellcrank pivotally mounted on the side plate 3 of frame 1. The bellcrank sensing element 38 has one arm 40 adapted to be engaged and depressed by the weight of a part at its station to rock the bellcrank and the opposite arm 41 is connected through a rod 42 to a crank-arm 43 fast on a rock shaft 44. Rock shaft 44, in turn, is journaled in the side plate 3 of the frame and guide tracks 32 and 33, and mounts a crank arm 47 between the latter and underlying the link-bar 28. Thus, with no part at station 6, the link-bar 28 rocks downwardly by gravity to an out-of-Iine relationship to the other link-bars as shown at station 5 in FIG. 3. On the other hand, when a part is located at, for example, station 6, it rocks the sensing bellcrank 38 clockwise and acts through the rod 42, and crank arm 43 to rock the shaft 44 and the crank arm 47 counterclockwise and lift the link-bar 28 into alignment with the other link bars, as shown in FIG. 4.

A rearward motion is initially applied to the forward linkbar 28 at the right hand end of the accumulating conveyor as view in FIG. 1 by means ofa lever 50 pivotally mounted intermediate its ends on a bracket 51. The lower end of the lever 50 is connected to the end of the piston rod 52 of a hydraulic ram 53, and the upper end of the lever is in alignment with the foremost link-bar 28 underlying the station 9 and operated by the sensing element 38 from station 10.

When a part P is present at each of the stations 1 to all of the link bars 28 are in line so that the reciprocation the foremost link-bar 28 by the rocker50 through a predetermined increment of movement is transmitted through the series of bars from one end of the conveyor to the other. When this occurs the end of the rearmost link-bar 28 engages a switch 54 to stop operation of the hydraulic ram 14 for actuating the reciprocating carriage 10 through a forward stroke, as well as stop'the operation of the hydraulic ram 53 for operating the lever 50. While not shown, it will be understood that a control system is provided incorporating additional switches 55 and 56 for synchronizing the operation of the hydraulic rams 14 and 53 so that the link-bars 28 are operated to set the part-advancing dogs 19 and prior to the actuation of the. reciprocating carriage 10 through a forward stroke. 1

As shown in FIGS. 2 and 3, the carriage 10 has depending tabs 58, one for each station, and mounting adjustable top stops 59 for resetting the link-bars 29 adjacent the end of its forward stroke. The adjustable stops 59 on the depending tabs 58 are aligned with and engage fingers 60 projecting laterally from the sliding blocks in which the end of pins 29 are journaled. As the carriage 10 moves through a longer increment of longitudinal movement to advance parts P than do the linkbars 28 for setting the dogs 19 and 20, alternate depending tabs 58 are located at different levels to permit them to pass by alternate fingers 60 projecting laterally from the blocks 30 of the pins 29 at different levels.

A preferred embodiment of the invention having now been described in detail, its mode of operation is now explained.

For purposes of description, let it be assumed that a part P is present at each of the stations 1 to 5 and 7 to 10, and that the station 6 is empty. Let it further be assumed that th the reciprocating carriage 10 has been retracted to its rearmost position and that the ram 53 has operated to set the link-bars 28 and dogs 19 and 20.

With the parts in the position illustrated in the drawings, sensing bellcranks 38 at the stations 10, 9, 8 and 7 forwardly of the empty station 6 will have been rocked by the weight of the parts P and acting through the connecting rods 42, crank arms 43, shafts 44 and crank arms 47 will have actuated the link-bars 28 underlying the stations 9, 8, 7 and 6 into alignment so as to be moved rearwardly as a solid bar by the rocker 50. The sensing bellcrank 38 at station 6, however, will not be depressed, which permits the link or read-out bar 29 underlying station 5 to fall by gravity to an out-of-line relation to the other link-bars as shown in FIG. 3. The longitudinal movement of the link-bar 28 underlying the station 6 will have actuated cam 26 rearwardly with respect to its roller to rock the cam 26 counterclockwise on the pivot pin 29, see FIG. 3. Movement of the upper edge surface 37 of the cam 26 relative to the follower tab 25 on the dog 19 rocks the dog against the action of gravity to its inoperative position illustrated. The rocking movement of the dog 19 will be tar transmitted through the crossbar 23 to simultaneously rock the dog 20 to its inoperative position. Also, all of the dogs 19 and 20 at the stations 7 to 10 forwardly of the empty station 6 will have been moved to an inoperative position in the manner described. However, the movement of link-bar 28 underlying the station 5 to an out-of-line position breaks the line of abutting linkbars so that those bars underlying stations 1 to 5 will not have been moved and thereby cancel the movement of the link at station 5 and all stations rearwardly of station 5. Thus, the dogs 19 and 20 at each of the stations are rocked by the counterweights 19b and 20b to an upright part-engaging position.

Following the setting of dogs 19 and 20, the ram 14 is operated to actuate the reciprocating carriage 10 through a forward stroke. During this forward stroke all of the dogs 19 and 20 at the stations 6 through 10 will be positioned below the parts resting on the seats 5 and 6 so that the carriage will move relative to the parts without moving them. However, the dogs 19 and 20 at the stations 1 through 5 will be in upright part-engaging positions and will advance parts P forward from one station to the next during the forward stroke of the reciprocating carriage l0.

Adjacent the end of the forward stroke of the reciprocating carriage 10, depending tabs 58, see FIGS. 1 and 2, will engage fingers 60 projecting laterally from the sliding pin blocks 30 to move all of the pins 29 and link-bars 28 back to their initial position. The carriage 10 will then be operated rearwardly by its ram 14 to its initial position.

As all of the parts P in stations 1 to 5 will have been advanced through one station, the station 6 will then be full, and the weight of the part operating through the sensing bellcrank 38 willrock the link-bar 28 underlying station 5 back to an inline arrangement with the other link-bars. With all of the stations 2 through 10 supplied with a part P, the plurality of linkbars 28 will transmit the movement from the rocker 50 through the line of link-bars to operate the switch 54 and stop reciprocation of the carriage l0 and operation of the rocker 50. However, when a part is removed from station 10 or any other station, operation of the hydraulic rams 14 and 53 will be initiated either by a part present limit switch at the unloaded station, or by a delayed action timer which cycles the entire unit at predetermined intervals to again advance parts along the conveyor and fill any empty stations in the manner described above.

FIGS. 5 through 8 illustrate a modified construction incorporating novel features of the present invention in a lift-andcarry conveyor for advancing parts.

As shown in FIG. 5, a perch 65 is provided at each station, to two of which are shown at stations 6 and 7 in the drawing. Each perch 65 has a depending leg 65a mounted to slide vertically on a side rail guide block of the frame. While not shown, a corresponding perch 65 is mounted to slide on the opposite side of the frame and the pair of perches support a part P. The lower end of the leg 65a of each perch is pivotally connected to the upper end of a connecting rod 67 of a twopart telescoping construction comprising an inner piston 68 and an outer cylinder 69 with a spring 70 therebetween. The spring 70 normally acts on the cylinder 69 to hold its perch 65 in a raised position A illustrated at station 6 in FIG. 5, but the spring is compressed by the weight of a part as illustrated at station 7 in FIG. 5 so that the two parts 68 and 69 of the connecting rod form a solid connection and move the perch to a lower position B.

The lower end of each connecting rod 67 is pivotally connected to a horizontally movable lift rail 71. The horizontally movable rail7l, in turn, is supported from rollers 72 projecting from one side thereof and riding on a stationary track 73 on the side of the frame and which has an inclined cam surface 74. Thus, when the rail 71 is moved horizontally to the left by hydraulic ram and rocker arm 81 pivotally mounted on the frame as viewed in FIG. 5, the rollers 72 ride down the inclined cam surface 74 and lower the connecting rods 67 and perches 65 at successive stations to a lower position D as shown at station 7.

Underlying the perches65 at each of the successive stations 1 to 10 is a second perch 75 at a level C and fixed at the upper edge of a reciprocating mechanism in the form of a horizontally movable carriage, not shown, see FIG. 5. Thus, when the perches 65 are lowered by the horizontally movable rail 71 to position D below the position C, the part P on each perch 65 is lowered onto the perch 75 of the horizontally movable carriage for moving the part forwardly. The horizontally movable carriage, like that shown in FIGS. 1 to 4, may be actuated by any suitable mechanism, illustrated in FIG. 5 as a hydraulic motor 77 connected through a piston rod 78 to a lug 79 depending from the carriage.

In accordance with the present invention, a connecting link 82 and link-bar 83 are provided at each station for controlling the vertical movement of its perch 65. The perches 65 at all stations forwardly of any empty station are locked in position B to prevent further transfer of the part to the perch 75 on the horizontally movable carriage. All perches 65 at the rear of any station which does not have a part P present are lowered to position D by the horizontally movable rail 71 to transfer the parts onto a perch 75 on the carriage for forward movement to the next adjacent station.

As shown most clearly in FIGS. 6 to 8, each connecting link 82 is pivotally connected at its forward end to the rearward end ofa link-bar 83 in the form ofa sliding block by a pivoted pin 84. Link-bars 83 are mounted to slide in a guideway 85 at the inner side of the frame and inner sides of the legs 65a of the perches 65. Each link-bar 83 mounts an outwardly projecting locking lug 86, see FIG. 7, which. in the forward position of the link-bar, is located at the right hand side of the perch, and in a rearward position enters a slot 87 in the perch and underlies a shoulder 88 on the upper edge of the slot, to lock the perch in raised position, see FIG. 8. Rearward movement of each link-bar 83 also actuates a pawl 92 mounted on a cross shaft 93 which transmits motion to a locking mechanism not shown, for locking the corresponding perch at the opposite side of the conveyor in its raised position. A roller 89 is mounted on the opposite end of the connecting link 82 which projects inwardly into a slot 90 in the rearward side of perch leg 650 having a bottom edge 91 for engaging and lifting the pin and rearward end of the link 82 out of alignment with the forward end of the next adjacent rearward link-bar 83 when there is no part P present at the station and perch 65 is at position A. However, when there is a part P present at the station, its weight depresses the perch to position B to lower the end of the link 82 into alignment with the next adjacent rearward link-bar 83.

The lift-and-carry conveyor illustrated in FIGS. through 8 is controlled in substantially the same way as the construction illustrated in FIGS. 1 to 4 and described above. An operating mechanism like the hydraulic ram illustrated in FIG. 1 actuates the foremost link 82 rearwardly to set the perches and parts mounted thereon for a'forward stroke of the carriage. The rearward movement of the foremost link 82 is transmitted to the link-bar 83 at the next adjacent rearward station. If there is a part on the perch 65 at said station the perch will be lowered to the position B illustrated in FIG. 5, which, in turn, will lower the forward end of the link 82 into alignment with the next adjacent link bar 83. Motion of the forward link 82 then will be transmitted to each adjacent link-bar throughout the conveyor in all of those stations having a part P mounted on the perch 65. On the other hand, if there is no part P at a station, such as station 6, the bottom edge 91 of the slot 90 in the perch 65 will lift the roller 89 and rearward end of the linkbar 82 out of line with the next adjacent rearward link-bar 83. Thus, roller 89 on the link 82 at the station 6 will ride along the top of and relative to the next adjacent rearward link-bar In all of those stations where a link bar 83 is moved rearwardly, the locking lug 86 will have moved into the slot 87 at the inward side of the perch and engaged the shoulder 88 of the perch to lock it in its upper position B, see dotted line position at station 7 in FIG. 5. Then when the horizontally moving rail 71 is moved to the left as viewed in FIG. 5, and downwardly as the roller 72 passes over the cam face 74, the parts 69 and 70 of each connecting rod 67 will move relative to each other while the perch 65 and part mounted thereon are locked in a raised position above the carriage. However, at those stations rearwardly of a station on which no part is present, the motion of the preceding link 82 is interrupted by the tilted link at the empty station are not moved into locking engagement with the legs 65a of the perches 65. The perches 65 then move downwardly to the position D illustrated in FIG. 5, to transfer the parts P mounted thereon onto the perches 75 of the carriage. The carriage is then moved forwardly by the hydraulic ram 77 to advance the parts toward the empty station. Following the forward movement of the carriage, the horizontally moving rail 71 is actuated back to its initial position to lift the parts from the perches 75 on the carriage onto the perches 65 on the frame.

The above sequence will be continued by successive actuations of the links 82 to set the parts, a rearward stroke of the horizontally moving rail 71 to lower the vertically moving perches 65, a forward stroke of the carriage to advance parts and a return stroke of the horizontally movable rail 71. It will be understood that the various motors for the link-bars 82, rail 71 and carriage 76 also will be coordinated in the proper sequence.

A still further modified construction of accumulating conveyor incorporating the present invention is shown in FIGS. 9 to 12. This form of conveyor has a simplified construction of sensing element and the link-bars and connecting links are mounted directly on the transfer bar for movement therewith. Each sensing element on a stationary part of the machine is constructed and arranged to directly actuate a link connecting adjacent bars to control the advance of parts.

As shown in FIGS. 9 and 10, dogs are provided at each station for engaging and advancing parts. Each dog 95 is pivotally mounted intermediate its ends on a reciprocating transfer bar 99 by a pivot pin 96. The dog 95 at each station has a part-engaging detent 97 projecting forwardly of the pin and a counterweight 98 extending rearwardly therefrom. The pivot pin 96 is so located as to cause the dog 95 to be rocked to an upright position by the counterweight 98 so as to engage and move a part P forward as the reciprocating transfer bar 99 is actuated through a forward stroke. The under side of the counterweight 98 has a cam follower surface engaged by a cam 104 on a link-bar 102 to rock the dog to an inoperative part-disengaging position.

The positioning of the dogs 95 is controlled by alternate links 101 and link-bars 102 generally similar to the links 82 and link-bar 83 of the construction shown in FIGS. 5 to 8 and described above. In other words, the forward end of each linkbar 101 is pivotally connected to the rearward end of a linkbar' 102 and each link carries a laterally projecting pin 103 at its rearward end for engaging the forward end of the next adjacent link-bar. However, when a link 101 is rocked about its forward pivot, pin 103 at its rearward end is moved out of alignment with and rolls on the top of the next adjacent rearward block to interrupt the movement of the link-bars 102. Each link-bar 102 has a projection 104 constituting the cam which, when moved relatively to its dog 95, engages the follower at the underside of the dog and tilts it from the position illustrated at station 6 in the position illustrated at station 7 in FIG. 9.

The sensing mechanism at each station for controlling the position of the links 101 comprises a rocking arm 105 pivotally mounted intermediate its ends on a pivot pin 106 and having a pad 107 at one side of the pivot pin and a counterweight 108 at its opposite side. Counterweight 108 tends to rock the sensing element-105 counterclockwise and raise the pad 107 above the surface of the rails 109 on which the parts are supported. However, when a part P is positioned at a particular station it overlies and depresses the pad 107 against the action of the counterweight 108 to rock the sensing element 105 clockwise.

Depending from the sensing element 105 is an arm 110 having a curved trip 111 which underlies the pin 103 at the rearward end of the link-bar 101. Thus, when the pad 107 is depressed by the weight of a part P to rotate the sensing element 105 clockwise, the tripping element 111 is moved away from the pin so that its link 10] is retained in alignment with the next adjacent intermediate block 102, as shown at station 5 in FIG. 9. However, when the pad 107 is unrestrained the counterweight 108'rotates the rocking element 105 counterclockwise which, in turn, rotates arm 110 and trip element 111 thereon to engage the pin 103 and lift the rearward end of the link-bar out ofalignment with the next adjacent block 102. Such movement interrupts the rearward motion through the remaining links 101 and link-bars 102 so that the dogs 95 are rocked to their part-engaging position at the rear of an empty station. During the next forward stroke of the reciprocating mechanism 99, parts at the rear of the empty station will move forwardly; but the parts at stations forwardly of the forwardmost empty station will not be engaged by the dogs 95 which are rocked to an inoperative position by the projections 104 on the link-bars with the counterweights 108 as shown at station 7.

In this modification the sliding link-bars 102 and connected links 101 are mounted directly on the reciprocating mechanism. As shown most clearly in FIGS. 11 and 12, the reciprocating mechanism is in the form of a carriage having a horizontal bed 116 mounted to reciprocate on rollers 117 and 118. Rigidly fixed to the bed 116 is a vertically arranged transfer bar 119 having narrow rails 120 and 121 to form a track therebetween for the sliding link-bars 102.

Also pivotally mounted on the left-hand side of the transfer bar 119 are the series of dogs 95 having the counterweights 98 normally holding dogs in an upright position with the lower end engaging the platform 116 to limit the rearward movement. The cams 104 project laterally from the link-bars 102 for engaging the side of the depending counterweight 98 to rock them from the position shown at station 6 to an inoperative position shown at station 7 in FIG. 9. The carriage may be reciprocated in the manner described above with respect to other modifications or may be reciprocated by an arm 125 projecting upwardly from a hydraulic ram through a slot 126 in the bed plate 116 and engaging compression springs 127. The opposite end of the springs 127 may be connected to the carriage which engages a stop at the end of its forward stroke and to endmost link 102 at the forward end of the conveyor. Thus, as the carriage 99 moves to the right through an advancing stroke, it advances parts until it engages a stop, but after the carriage stops movement is continued through the arm 125 and springs 127 to advance the endmost link 102 relative to the carriage. During such relative movement the string of links 101 and link-bars102 are extended to reset them to an initial position during which time the springs 127 may be compressed. At the beginning of movement of the carriage driving means through a return stroke the endmost link 101 is moved rearwardly relative to the carriage by the springs 127 to set the dogs 95 for the next forward stroke. If there is no part present at a particular station the feeler element 105 will rock counterclockwise and raise the pin 103 on link 101 to intercept or cancel motion to the link bar 102 located rearwardly of the empty station and thereby release all of the dogs 95 rearwardly of said empty station to advance parts during the next forward stroke of the carriage.

FIGS. 13 to 15 disclose another modified construction for a walking beam type of conveyor. In this construction the parts P to be advanced are supported on perches 130 projecting upwardly from side plates at opposite sides of the frame, see FIGS. 14 and 15. A sensing arm 131 for each station is pivotally mounted on a side rail 132 of the machine frame on offset pivots 133, as shown at the station 1 at the left-hand side of FIG. 14. The sensing element 131 has a curved portion 1310 at its upper end for feeling a part at its particular station and a counterweight 134 at its lower end which underlies the side plate 132 of the frame on which it is pivotally mounted.

Each sensing arm-131 is normally rocked counterclockwise by its counterweight 134 when no part is at its particular station and such rocking movement is limited by an adjustable stop 135. The top surface of the counterweights 134 underlying the side plate 132 of the frame are in the form of a cam 136 underlying the outer end of a pin 137 at the end of a link 138. The link 138, in turn, is pivotally connected to one end of a link-bar 139 and the inner end of the pin 137 at its opposite end projects into a slot 140 in the rearward end of the next adjacent link-bar, see FIG. 14. The feeler arm 131 operates the control mechanism in a slightly different manner from the arrangements previously described in that the slot 140 in the link-bar 139 has a horizontal section 140a and an upwardly directed vertical section 1 Thus, when a part is located at stations 1 and 5 the feeler'arm 131 is rocked clockwise to raise the cam 136 on the counterweight 134 and hold the pin 137 in the vertical section 140b of the slot in the next adjacent linkbar 139 to transmit motion through successive link-bars. On the other hand, when there is no part present as at the stations 6 and 7 the feeler arms 131 rock counterclockwise and lower the cam 136 which causes the pin 137 to fall into the horizontal portion 140a of the slot and permit relative motion between the link and next adjacent link-bar 139.

&

A perch 145 is provided at each station which is movable from a part-disengaging position to a part-engaging position. Each perch 145 is of a composite construction including the upwardly inclined arm 146 and an arm 147 as viewed at station 5. The arms 146 and 147 are in a rigid structure mounted for pivotal movement on a shaft 148 on the transfer carriage 150, see FIG. 15. It will be understood that a pair of spaced perches 145 and 145a are provided at each station and connected by the shaft 148. Projecting laterally from the arm 146 is a roller 151 for actuating the perch 145 from the lowered position illustrated at station 7 to raised position illustrated at station 5. Each of the link-bars 139 has an upwardly extending strut 152 and an inwardly directed plate or platform 1.53 with an upwardly projecting cam plate 154 having an inclined cam surface 154a and a horizontal supporting surface 154b at the upper end of the cam surface.

The carriage is reciprocated through forward and return strokes by a hydraulic motor 155, see FIG. 15, having a clevis 156 for connecting it to a stationary part 157 of the machine frame and a clevis 158 connected to the carriage. As further shown in FIG. 15 the frame 157 supports the side rails 132 and transverse beams 159 extending between the sides of the frame.

With the modified construction illustrated in FIGS. 13 to 15 a suitable means suchas a hydraulic ram actuates the innermost link 138 to the right, which, operating through the linkbars 139, pulls all of the connected links and link-bars to an extended position. Movement of the link-bars 139 to the right also moves the cams 154 to the right, and, operating through the rollers 151, rocks all of the perches 145 upwardly as shown at stations 1, 5 and 6 in FIG. 14. If a part is present at any station, such as station 5, feeler arm 131 at that station will rock clockwise and raise the cam surface 136 on the counterweight 134 to lift the pin 137 on its link 138 to hold it in the vertical section 1401; of the slot of its next rearward linkbar 139. On the other hand, if there is no part at a particular station, as shown in station 6, the feeler arm rocks counterclockwise to lower the cam 136 and pin 137 to align it with the horizontal section 140a of the slot 140 in its corresponding link-bar 139.

When the hydraulic cam actuates the endmost link through a return stroke to the left and there is a part present at each station, the motion is transmitted through successive links 138 and link-bars 139 from one end of the conveyor to the other to move the corresponding cams 154 attached to the blocks to the left in the manner illustrated at station 7 to lower the perches to an inoperative or part nonengaging position. On the other hand, if there is no part at a station, such as station 7, the cam 136 will lower the pin 137 on link 138 into the horizontal portion 140a of slot 140 at the next rearmost station 6 to permit a loss motion between the link and link-bar 139. The cam 154 at the next rearmost station and all stations rearwardly thereof remain in their advanced position to hold perches 145 at all stations rearwardly of the empty station in a raised position. The side plates 160 and 160a have tracks 161 and 161a and the carriage reciprocates on rollers 162 and 162a located under said tracks. The rollers 162 and 1620, in turn, are mounted on side rails 163 and 163a also having tracks 164 and 164a for receiving rollers 165 and 165a at the ends of crank arms 166 and 166a on a rock shaft 167. Rock shaft 167 has a third crank arm 168 connected at its outer end to a hydraulic motor 169.

Thus, after the perches 145 have been set to a part-lifting position, the hydraulic motor 169 is expanded to operate through the crank arm 168, rock shaft 167 and crank arms 166 and 166a to raise the carriage 150. Those perches 145 in an upright position then lift the parts from the stationary perches 130. Hydraulic motor is then expanded to move the carriage 150 through a forward stroke and carry the lifted parts to the next forward position. Hydraulic motor 169 is then contracted to lower the carriage 150 to position the parts on the stationary perches on the frame at the forward station. During the forward stroke of the carriage 150 the lowered perches 145 at stations 6 and 7, see FIG. 14, will not pick up parts from the stationary perches, but during the rearward stroke all of the perches will clear the parts at the respective stations.

FIG. 16 discloses a modified construction to adapt the different forms of accumulating conveyors described above for use with other takeoff mechanisms, such as a loader for a machine tool. Many times the actuating mechanism for operating the shuttle, or lift-and-carry platform or walking beam as well as the mechanism for reciprocating the endmost link of the control for setting the part-advancing elements interferes with the positioning of other takeoff equipment closely adjacent the exit end of the accumulating conveyor. The modified construction illustrated in FIG. 16 provides a remote operating control for the last two stations which, in turn, operates on the first link of the series of pivotally connected links and link-bars to eliminate all mechanism beyond the exit station and actually provide an open space under the part at the last station.

Referring to FIG. 16, the improved construction illustrates the last two stations of an accumulating conveyor of the type shown and described above and indicated as stations A and B. Station A is the last station having identical controls. Station B is similar to station A except for the operation of its link-bar. Stations C and D are of a unique construction to transfer mo tion of their feeler mechanism back to the link at station A. The improved construction comprises a feeler bar 170 at the last station D mounted on a pivot pin 171 to extend rearwardly and downwardly. The feeler bar 170 has a counterweight 172 at the opposite side of the pivot to cause it to rock counterclockwise and the feeler bar has an angularly extending arm 173 with a pin 174 projecting laterally from its end. Feeler bar 170 also has an arm 175 extending at right angles from its opposite side and this arm has a cam surface 176 adjacent its outer end.

In the illustrated embodiment the parts are advanced by a shuttle 177 mounted to reciprocate in a suitable mounting on the frame. Part-advancing dogs are mounted to rock on the shuttle 177 at stations A, B and C and each has a part-engaging detent 181 at its upper end and a counterweight 182 at its lower end to normally rock the dog about its pivot pin 183 to an upright part-engaging position as shown at station B. However, the dog 180 at station C has a follower roller 184 engaged by the cam surface 176 on the arm 175 projecting laterally from the feeler bar 170. When there is a part P at the station D, as illustrated, the feeler bar 170 and angularly extending arm 175 are rocked clockwise to engage cam 176 with the follower roller 184 on the dog 180 to rock the dog to its lowered part nonengaging position. On the other hand, if there is no part P at the station D, the feeler bar 170 rocks counterclockwise to lower the cam 176 and permit the dog to move to an upright part-engaging position.

A feeler bar 170 is provided at station C and has a laterally projecting arm 173 and projecting pin 174 the same as the feeler bar at station D.

At station B a feeler bar 170 and dog 180 are provided of the same construction as at station C. However, at station B an endmost control link 185 is provided which is pivotally connected at its forward end to an actuating rocker 189 and has a pin 186 at its rearward end for cooperation with a slot 187 in a link-bar 188 of the same general construction as previously described. The slot 187, however, has an upright portion 187a and a right angular longitudinal portion 18711 with each of the slot portions inclined at an angle to the vertical and horizontal, respectively. The lower end of the rocker 189 is connected to the piston 190 ofa hydraulic actuating mechanism 191.

Mounted on the frame at one side of shuttle 177 is a horizontal bar 200 mounted on links 201 and 202 of equal length for vertical movement while held in a horizontal position. At the rearward end of the bar is a laterally projecting cam 203 which underlies the pin 186 of the endmost link 185 on the shuttle 177 so that when the bar 200 is in raised position it will raise the pin 186 projecting laterally from link 185 into alignment with the longitudinally extending portion 187b of the slot 187 in the link-bar 188. It will be observed with this arrangement that the endmost link 185 of the setting control mechanism is displaced forwardly two stations away from the end of the conveyor to permit an unloader 204 to be positioned under the part at station D.

In operation, rocking movement of any of the feeler bars at stations B, C and D in a counterclockwise direction when no part is present causes its laterally projecting pin 174 to engage the underside of the bar 200 and raise it to the position illustrated in FIG. 16. This indicates that some station forwardly of the station A is empty and sets the dog 180 at the next rearmost station to advance a part. During reciprocation of the endmost link 185 a lost motion is produced between it and the next rearmost link-bar 188 to position all of the dogs rearwardly of the empty station in position to advance parts. However, if there is a part at station D as illustrated, the sensing bar 170 and arm will hold the dog 130 at station C depressed to prevent advance from the station C to the station D. When no part is present at the station B, the feeler bar 170 rocks counterclockwise so that its pin 174 engages and lifts bar 200. Cam 203 then lifts the pin 186 at the end oflink 185 into alignment with the longitudinal portion 18717 of the slot 187 in the next rearward link-bar 188, to permit a lost motion therebetween. This lost motion permits the dog at station B to move to its upright position under the action of counterweight 172 to advance a part from the station B to the station C, If a part is present at all of the stations D, C and B, the bar 190 will fall by gravity to its lowermost position and thereby permit the pin 186 in the endmost link to rest in the upright portion 187a of the slot 187 and advance the link-bar 188 to which it is connected. The conveyor then operates in a conventional manner to advance parts as required.

FIG. 17 illustrates a still further modified construction of transfer mechanism for the last station which permits a close association with other machine tools for feeding parts thereto. The accumulating conveyor illustrated in FIG. 17 has spaced side rails 301 with spaced seats for supporting articles at successive stations as previously described. A shuttle 302 is mounted to reciprocate between the side rails 301 in the manner previously described, but the end of the shuttle terminates short of the end of the side rails. Pivotally mounted adjacent the end of the shuttle 302 is a transfer bar 303 in the form of a lever having a perch 304 at its outer end and a follower roller 305 at its other end. Roller 305 is located in a slot 306 in a reciprocating yoke 307 for movement from the position illustrated in full lines to the position illustrated in dash lines in FIG. 17. Underlying the roller 305 in the dash line position illustrated in FIG. 17 is a track 308 along which the follower roller reciprocates when there is a part in the station overlying the perch 304. When the roller 305 is reciprocated along the track 308 the perch 304 underlies the part and merely moves relative thereto.

However, when a part is to be transferred from the last station to a part feeder 309 of another machine tool, the yoke 307 is moved downwardly to align the follower roller 305 with a cam track 310. During the downward movement of the follower 305 the transfer bar or lever 303 is rocked counterclockwise to cause the perch 304 to lift the part from the seats on the side rails for transfer to the part feeder 309. With the follower roller 305 moved downwardly, the reciprocation of the shuttle 302 through a forward stroke causes the follower roller 305 to follow the cam track 310 which first raises the part as it moves forwardly and then lowers the part during a return stroke of the shuttle onto the part feeder 309. The follower roller continues to rise until it is in alignment with the track 308. During the return stroke of the shuttle 302 the follower roller 305 will follow the horizontal track 308 to its initial position.

The yoke 307 for controlling the movement of the transfer bar 303, either to move relative to the part or lift the part and move it to the part feeder 309, is controlled by a sensing mechanism (not shown) which actuates the yoke at its upper or lower level. The sensing mechanism may be a conventional electric or pneumatic sensing device or may be a mechanical sensing device as described above with respect to the preceding modifications. In any case, the sensing mechanism would operate the pneumatic or hydraulic ram 311 for raising and lowering the yoke 307 to properly position the follower roller 305 for the particular function intended. It is believed that the mode of operation will be obvious to one skilled in the art from the above description.

It will now be observed that the present invention provides an improved mechanically operated accumulating conveyor for maintaining a supply of readily available parts for use as needed. It will also be observed that thepresent invention provides a mechanically operated accumulating conveyor which is mechanically controlled by the transmission of a motion to all stations forwardly of anempty station to prevent the advance of parts and interrupts the transmission of motion to cause the advance of parts at all stations rearwardly of the empty station. It will also be observed that the present invention provides a mechanical control for an accumulating conveyor which is of relativelysimple and compact construction, economical to manufacture and one which is reliable in operation.

While the several embodiments of the invention are herein illustrated and described, it will be understood that further changes may be made in the construction and arrangement of elements without departing from the spirit or scope of the invention, Therefore, without limitation in this respect, the invention is defined by the following claims. 1

1. In a conveyor for intermittently advancing parts of the type having longitudinally spaced seats for supporting parts at successive stations, a reciprocating mechanism having a partengaging means at each station for engaging and advancing a part to the next adjacent station during a forward stroke, the combination with said elements of a control mechanism for positioning said part-engaging means at each station. at the rear of any empty station to engage and advance parts and positioning saidmeans at each station forwardly of said empty station to disengage parts, said control mechanism comprising a link-bar for each station, means for reciprocating one endmost link-bar prior to a forward stroke of the reciprocating mechanism, said link-bars being articulated and constructed to transmit motion through successive stations when positioned in one arrangement and permit relative movement therebetween when positioned in another arrangement, and a movable sensing element at each station and actuated by the presence of'a part at its station to move a corresponding linkbar to a position relative to said other link-bars'whereby to permit relative movement therebetween at any empty station and interrupt the reciprocation of the link-bars at one side of said empty station.

2. A conveyor in accordance with claim 1 in which the linkbars at adjacent stations are connected by intermediate blocks, and each block having a cam for engaging and setting the part-engaging means.

3. An accumulating conveyor in accordance with claim 2 in which the seats on the reciprocating mechanism are perches pivotally mounted thereon, and a cam for each link-bar and movable relative to its corresponding perch to rock the latter to engage and lift a part.

4. An accumulating conveyor in accordance with claim 3 in which one end of each link is connected to one block and the other end of said link having a laterally projecting pin, and L- shaped groove in each block into which the link pin projects, the sensing means at each station moving the link pin into the vertical portion of said groove to transmit motion to the next link and the horizontal portion to permit relative movement between adjacent links, and the cam being actuated by its corresponding block to rock the part-supporting perch.

5. A conveyor in accordance with claim 1 in which additional stations are provided beyond the endmost link-bar of the series of links, a separate sensing element for the endmost link, means operated by the sensing element for for setting the part-engaging means and the preceding station, a sensing element for setting the endmost link-bar and a separate member actuated by the separate sensing element for setting the endmost link-bar independently of the last-named sensing element.

6. A conveyor in accordance with claim 5 in which several stations are provided beyond the endmost link-bar, a sensing element at each of said stations, said separate member comprising a bar, links connecting the ends of said bar to cause the bar to rock in a parallel path, projections on each of the sensing elements underlying the bar to raise the bar when no part is present at any of the stations beyond the endmost linkbar, and said bar engaging a pin on the endmost link-bar when the bar is raised.

7. An accumulating conveyor comprising, longitudinally spaced seats for supporting parts at successive stations reciprocating mechanisms having a part engaging means at each station for intermittently advancing parts at all stations at one side of an'empty station without advancing parts at the other side of said empty station, means for relatively moving the part-engaging means and seat for supporting parts at each station to cause the part-engaging means to engage and advance a part during a forward stroke of the reciprocating mechanism when the part-engaging means and seat are in one relationship and disengage the part when in another relationship, said last named means comprising a movable setting element at each station for controlling the relative movement of a part engaging means and seat, said setting elements being mounted to slide in abutting end to end relationship relative to .the part-engaging means and seat at each station and in a group relative to the remaining elements at one side of an empty station, actuating means operable prior to the reciprocating mechanism .to slide setting elements and control the relationship of the part-engaging means and seat at each station, and sensing means at each station movable in response to the presence of a part and connected to selectively position its corresponding setting element for movement by the actuating means. 7

8. An accumulating conveyor in accordance with claim 7 in which the sensing means at each station is the seat for normally supporting a part, said seat being mounted for movement relative to the part-engaging means, biasing means for moving the seat to one position when no part is present at the station, said seat being movable to another position by the weight of the part against the action of the biasing means, and said movable seat being-connected to position its corresponding setting element for actuation by the actuating means to a selected position. I

9. A conveyor for intermittently advancing parts comprising seats spaced longitudinally for supporting parts at successive stations, means for advancing parts at the rear of an empty station without advancing parts forwardly of said station comprising, a reciprocating mechanism, part-engaging means mounted on the reciprocating mechanism at each station for movement from an operative part-engaging position to an inoperative part-disengaging position, means for actuating the part-engaging means at each station to one position, a link-bar at each station having means for actuating each part-engaging means to its other position, means for bodily moving the linkbar at one endmost station in one direction to set its corresponding part-engaging means to one of its part-engaging and part-disengaging positions, means for mounting each linkbar for movement from an in-line relation to the other linkbars for end-to-end movement as a continuous bar to an outof-line relation to the other link-bars to permit relative movement therebetween, and a sensing element at each station movable in response to the presence of a part at said station to actuate said link-bar at the next rearward station into and out of alignment with the other link-bars whereby to move all of the link-bars relative to the part-engaging means at one side of the empty station and disconnect the remaining link-bars from movement relative to the part-engaging means.

10. A conveyor for intermittently advancing parts having a frame with successive stations longitudinally spaced thereof and a seat at each station for supporting a part, a reciprocating mechanism having a part-engaging means at each station for engaging and advancing a part to the next adjacent station during a forward stroke and disengage parts during a rearward stroke, control mechanism for setting the part-engaging means at each station to advance parts rearwardly of any empty station without advancing parts forwardly of the empty station, said control means comprising a chain of articulated elements mounted for sliding movement with at least one element at each station rockable from a connecting to a disconnecting relation to adjacent elements, means for reciprocating the endmost element of the chain to extend all of the elements to a connecting relationship, a feeler means at each station movable to one position in response to the presence of a part and movable to a second position when there is no part present at said station, each feeler means being operatively connected to rock one of said articulated elements to its disconnecting relation to adjacent elements of the chain when no part is present, and each of said articulated elements at each station having means for actuating the part-engaging means.

11. A conveyor for intermittently advancing parts comprising seats spaced longitudinally for supporting parts at successive stations, means for advancing parts at the rear of an empty station without advancing parts forwardly of said station comprising a reciprocating mechanism, dogs pivotally mounted on the reciprocating mechanism at each station for rocking movement from an operative part-engaging position to an inoperative part-disengaging position, said dogs being actuated by gravity to one position, a cam for actuating each dog to its other position, means for bodily moving the cam at one endmost station to set its corresponding dog to one of its part-engaging and part-disengaging positions, means for mounting each cam for movement from an in-line relation to the other cams for end-to-end movement as a continuous bar to an out-of-line relation to the other cams, and a sensing element at each station movable in response to the presence of a part at said station to actuate said cam at the next rearward station into and out of alignment with the other cams whereby to move all of the cams relative to the dogs at one side of the empty station and disconnect the remaining cams from movement relative to the dogs.

12. A conveyor for intermittently advancing parts comprising side frames with seats spaced longitudinally for supporting parts at successivestations, means for advancing parts at the rear of an empty station without advancing parts forwardly of said empty station comprising a reciprocating mechanism, a dog pivotally mounted on the reciprocating mechanism at each station for rocking movement from an operative part-engaging position to an inoperative part'disengaging position, said dogs being actuated by gravity to an operative part-engaging position for advancing a part during a forward stroke of the reciprocating mechanism, means at each station for actuating the dog at said station to an inoperative part-disengaging position, said means including a plurality of link-bars pivotally mounted for rocking movement from an in-line relationship with the other link-bars to operate as a continuous bar throughout the plurality of stations to an out-of-line relationship to the other link-bars to interrupt the transmission of movement, means for actuating the link-bar at the forward station longitudinally, a sensing element at each station movable in response to the presence and absence of a part at said station, and said sensing element at any empty station being connected to rock the link-bar'at the next adjacent station out of line with the other link-bars to discontinue movement of all link-bars at the rear of said empty station.

13. A conveyor inaccordance with claim 12 in which the means at each station for actuating the dog is a cam for rocking the dog as it advances relative thereto, and each cam being connected for longitudinal movement with the link-bar at said station.

14. A conveyor in accordance with claim 13 in which the cam at each station is pivotally mounted for rocking move ment for an inoperative position to an operative position for actuating the dog, and a stationary pin for engaging each cam as it is advanced by its corresponding link-bar for rocking it to actuate the dog at said station.

' 15. A conveyor in accordance with claim 13 in which a pair of link-bars is provided at each station, the cam being mounted between each pair of link-bars, and a common pin for connecting the link-bars and cam for rocking movement.

16. A conveyor in accordance with claim 12 in which the reciprocating mechanism comprises rollers projecting inwardly from the sides of frame, a carriage having side rails mounted to roll said rollers, a rock shaft at each station extending between the sides of the carriage and mounting a pair of the spaced dogs for advancing parts, said dogs being counterbalanced to be rocked to an operative position for engaging a part at said station, a pair of said link-bars at each station mounted to slide under said dogs and a cam mounted between said links for engaging one of said dogs to rock it and the shaft to an inoperative position below the part, and a roller engaged by each cam as it is advanced with its link-bars to rock the cam.

17. A conveyor in accordance with claim 12 in which the pivoted link-bars are mounted to slide between upper channels and underlying pins, and said sensing element at each station having an arm underlying the link-bar at the next adjacent station for moving it to an in-line position with the other links when a part is present at said station and releasing said link to rock to an out-of-line position if no part is present to discontinue longitudinal movement of all link-bars at the rear of any station at which no part is present.

18. A conveyor in accordance with claim 12 in which a motor is provided for operating the reciprocating mechanism for advancing parts, the means for sliding the link-bar at the forward station is a motor, an electric control for starting and stopping said motors, and a limit switch actuated by the linkbar at the rearmost station when a part is present at each station to discontinue operation of the motors.

19. A conveyor in accordance with claim 12 in which projections are provided on the link-bars and tabs on the reciprocating mechanism for engaging projections from the link-bars to reset all of the link-bars to their initial position adjacent the end of a forward stroke of the reciprocating mechanism.

20. A conveyor in accordance with claim 19 in which the projections on alternate link-bars are located at different levels, and the alternate tabs on the reciprocating mechanism being located to engage alternate projections only whereby to adapt the reciprocating mechanism to move through a longer stroke than the link-bars.

21. An accumulating conveyor comprising a frame, spaced seats on the frame for supporting parts at successive stations along the frame, a reciprocating mechanism having seats corresponding to the seats on the frame, means for mounting at least one of the seats on the frame and reciprocating mechanism at each station for relative movement vertically to control the intermittent advance of parts horizontally by said reciprocating mechanism, said last named means including a sliding link-bar at each station for controlling the relative vertical movement of said seats on the frame and reciprocating mechanism to move one of the seats upwardly when the linkbar is in one longitudinal position and disengage the relatively movable seat when the link-bar is in another longitudinal position, means for advancing an endmost link-bar, and sensing means at each station movable in response to the presence or absence of a part at said station for moving a link-bar into and out of alignment with the other link-bars whereby to permit relative movement of the seats and an advancement of parts at all stations at the rear of any empty station and prevent relative movement of the seats and advancement of parts at all stations forwardly of the empty station.

22. An accumulating conveyor in accordance with claim 21 in which the seat on the frame is a perch mounted to slide vertically thereon and having a seat located above the reciprocating mechanism, the link-bar having a locking lug thereon for locking the perch in its upper position when its link-bar is advanced, and means for bodily lowering all of said unlocked perches prior to a forward stroke of the reciprocating mechanism to lower the parts thereon onto the reciprocating mechanism.

23. An accumulating conveyor in accordance with claim 22 in which a motor is provided for advancing the endmost forward link rearwardly to set the locking means on the link-bar at each station, a motor for bodily lowering all of the unlocked perches, and a motor for actuating the reciprocating means horizontally.

24. An accumulating conveyor in accordance with claim 22 in which each vertically slidable perch has a depending leg slidable in a guide on the side of the frame, a reciprocating rail mounted on a cam track for movement to upper and'lower levels as it reciprocates, the means for bodily lowering'the unlocked perches comprising a two-part telescoping rod for each perch connecting the depending leg of the perch to the reciprocating rail, and a spring between the parts of the telescoping rod whereby to hold the perch in a raised position when no part is present, lower the perch against the action of the spring to a position above the perch on the reciprocating mechanism when a part is present and lower the perch on the frame below the perch on the reciprocating mechanism when the perch is unlocked to transfer the part onto the reciprocating mechanism.

25. An accumulating conveyor for intermittently advancing parts comprising seats spaced longitudinally for supporting parts at successive stations, means for advancing parts at the rear of an empty station without advancing parts forwardly of said station comprising, a reciprocating mechanism, part-engaging means for each station mounted on the reciprocating mechanism for movement from a part-engaging position to an inoperative part-disengaging position, control mechanism mounted on said reciprocating mechanism for movement therewith including a link-bar for each station for setting the position of its corresponding part-engaging means, means for reciprocating one endmost link-bar relative to the reciprocating mechanism prior to its forward stroke, said link-bars being constructed to transmit motion through successive stations when positioned in one arrangement and permit relative movement therebetween when positioned in another arrangement, and a movable sensing element at each station and actuated by the presence of a part at its station to move a cor responding link-bar to a position relative to said other linkbars whereby to permit relative movement therebetween at any empty station and interrupt the reciprocation of the linkbars at one side of said empty station to set its part-engaging means.

26. An accumulating conveyor comprising longitudinally spaced seats for supporting parts at successive stations, reciprocating mechanism having a part-engaging means at each station for intermittently advancing parts at all stations on one side of an empty station without advancing parts from any station at the other side of said empty station, means including a sliding link-bar at each station and mounted on the reciprocating mechanism for setting the part-engaging means to engage and advance a part during a forward stroke of the reciprocating mechanism when the bar is in one longitudinal position and disengage the part when the bar is in another longitudinal position, means connected to actuate the link-bar at each station longitudinally through a fixed increment of movement, a stationary pivot pin at each station, and sensing means at each station comprising a one piece member pivotally mounted on the pivot pin intermediate its ends to rock on said pin, said member being rocked to one position by a part at its station and to another position when the station is empty, and said member engaging and positioning the free end of its corresponding link-bar when no part is present at the station to set the art-engaging means to engage a part.

27. n accumulating conveyor in accordance with claim 26 in which the part-engaging means at each station comprises at least one dog pivotally mounted on the reciprocating mechanism intermediate its ends and having a part-engaging detent at one side of its-pivot and a counterweight at the opposite side of itspivot, and a cam at each station operated by the link-bar at said station for actuating the dog to an inoperative part-disengaging position when a link-bar is moved by a preceding link-bar.

28. An accumulating conveyor in accordance with claim 27 in which the link-bars at adjacent stations are connected by intermediate blocks, and each block having the cam for engaging the counterweight to rock the part-engaging dog to its inoperative position.

29. An accumulator in accordance with claim 28 in which the link-bar at each station has its forward end pivotally connected to the rearward end of a block, a roller projecting inwardly from the rearward end of link in alignment with the forward end of the next adjacent block, and the one-piece sensing member having an arm underlying the extended end of the pin for rocking the link-bar upwardly and out of alignment with the end of the next adjacent block.

30. An accumulating conveyor comprising a frame having means for supporting parts at spaced stations along the frame,

reciprocating mechanism having a dog for each station pivotally mounted thereon, each dog having a part-engaging detent at one side of its pivot and a counterweight at the opposite side of its pivot for normally positioning the detent in a part-engaging position, means including alternate link-bars and blocks mounted to slide on said reciprocating mechanism, one of said blocks being provided for each station and each block having a slot adjacent one end, a link for each station pivotally connected at the end of a block opposite the end having a vertical slot and having a laterally projecting pin at its opposite end, the pin on each link entering the slot in the next adjacent block to transmit motion between adjacent blocks when the link is in one pivoted position and being located at one side of the slot to interrupt motion from one block to the next when the link is in another pivoted position, a cam on each block for actuating the dog at its corresponding station to a part-disengaging position when the block is moved longitudinally of the reciprocating mechanism, a sensing means at each station movable in response to the absence of a part and connected to actuate a corresponding link to its block-disengaging position, and means for resetting the blocks and links to their initial position after the parts have been advanced. 

